In high pressure collision based RF/DC PVD (e.g., about 30-150 mT), metal atoms and background gas may be ionized through either electron impact ionization or penning ionization, resulting in much higher ionization fraction than conventional DC plasma. A plasma sheath voltage can be formed between the plasma and the substrate to provide high acceleration energy for both metal ions and Ar+. The inventors have discovered that high energy sputtering due to the acceleration of the ions caused by the sheath could lead to negative impacts on layer properties on the substrates and/or inside high aspect ratio features, such as undesired crystal orientation and/or sputter-induced overhang at the mouth of a high aspect ratio feature.
Thus, improved methods for depositing metal-containing layers on substrates are provided.